Cutting wire assembly for use with a catheter

ABSTRACT

A method of treating a lesion in a body lumen to enlarge a passageway in the lumen including inserting a cutting member and tracking member through a first lumen of a catheter, withdrawing the catheter from the cutting member and tracking member, inserting the catheter over the tracking member and leaving the cutting member outside the catheter, and expanding a portion of the catheter to move the cutting member into cutting contact with the lesion. A device for treating a lesion in a body lumen including a cutting member and tracking member is also provided.

This application claims priority from provisional application Ser. No.61/390,217, filed Oct. 6, 2010, the entire contents of which areincorporated herein by reference.

BACKGROUND Technical Field

This application relates to a system and method for treating stenoticlesions of a vessel and more particularly relates to a cutting wire foruse with a catheter to open stenotic lesions in vessels.

Background of Related Art

Several methods have been utilized to treat stenotic lesions of vessels.With stenotic lesions, the vessel diameter is constricted and thereforeattempts have been made to widen this constriction. One method is aninvasive surgical procedure where the vessel wall is cut open and theportion containing the plaque or other constricting structure isremoved. This procedure is traumatic, complex, and results in a longrecovery time for the patient. It also causes a weakening of the vesselwall since a portion of the wall is removed. A weakened wall canultimately result in an aneurysm which is a dilatation (expansion) ofthe artery, which adversely affects vessel function and if notsurgically treated could be life threatening to the patient.

In order to reduce trauma to the patient, reduce the patient recoverytime and reduce hospital costs, minimally invasive procedures have beendeveloped to treat stenotic lesions. Balloon angioplasty is one suchmethod. In angioplasty, a balloon is placed in the stenosed (restricted)portion of the vessel and inflated to compress the plaque against thevessel wall, thereby increasing the lumen in the vessel to improve bloodflow. That is, the balloon is inflated to push the lesion radiallyoutwardly to widen the passageway. Some stenotic lesions are resistantto conventional pressure balloons. Consequently, high pressure balloonshave been developed to treat resistant stenotic lesions. However, suchhigh pressure balloons apply more force and increase the risk of vesseltrauma and rupture. Moreover, sometimes lesions are even resistant tothese high pressure balloons.

Additionally, the use of these angioplasty balloon catheters oftentimeshave only short term effect as it has been found that restensoisfrequently occurs after such treatment.

In an attempt to address such drawbacks as reducing the likelihood ofrestenosis and trauma, as well as to treat vessels with highly resistantlesions, cutting balloon catheters were developed. One such device isdisclosed for example in U.S. Pat. No. 5,196,024 which describes acatheter with a balloon and longitudinal cutting edges. One of the manydisadvantages of this device, however, is it requires modifications ofballoon catheters which significantly increases the cost of thecatheter. Another disadvantage is that instead of using the proceduralcatheter, a different catheter may be required with a cutting balloon.Consequently, the surgeon would need to decide prior to the procedurewhich type of catheter to utilize, although this may not always bepractical as the information to determine the type (e.g. resistance) ofthe lesion may not be available until the lesion is accessed and theextent of the disease is known. Thus, for example, the surgeon mayinsert an angioplasty catheter, inflate the balloon and find that it isinsufficient to widen the vessel passageway. The surgeon would then needto conduct the time consuming task of removing the catheter andinserting a cutting balloon catheter, threading it through the vascularsystem over a guidewire. Since the catheters are inserted from a remotesite, e.g. through the femoral artery, these catheter exchanges taketime and increase trauma to the patient. Additionally, it adds to thecost of the procedure since two catheters would be required. In order toproperly treat the diverse size and condition of each lesion a largeinventory of multiple sized cutting balloons would be required.

Conversely, in certain procedures, utilizing a cutting balloon in softlesions increases the risk of trauma or damage to the vessel andtherefore it would not be desirable to use a cutting balloon catheter.Thus, an exchange for an angioplasty catheter would be necessary.

Such catheter exchanges might also require guidewire exchanges since thestandard 0.035″ guidewire utilized for an angioplasty catheter may betoo large for the 0.018″ cutting balloon catheter. The guidewireexchanges complicate the procedure, increase the risk to the patient andincrease the procedure time, thereby increasing costs to the patient.

U.S. Pat. No. 7,131,981 attempts to address the foregoing issues byproviding a conversion device comprising an insertion tube insertableinto the normal 0.035″ guidewire lumen of an angioplasty catheter. Thisdevice would not work for angioplasty catheters with small guidewirelumens. The tube has two jacket segments and a guide insert devicehaving a channel and four guide channels. Because of the complexity ofthe device, the cutting elements in the four channels would need to besufficiently thin to be maintained in the smaller diameter device. Suchthin (small diameter) cutting elements however may be too flexible andnot have adequate stiffness to be effective. Additionally, the cuttingelements are attached at one end, having an opposite free end which canpotentially damage and perforate the vessel wall during use.

The need therefore exists for an improved, more simplified device andmethod to enable the selective use of a cutting wire for treatingstenosis.

SUMMARY

The present invention overcomes the disadvantages and deficiencies ofthe prior art.

In one aspect, the present invention provides a method of treating alesion in a body lumen comprising inserting a cutting member andtracking member through a first lumen of a catheter, withdrawing thecatheter from the cutting member and tracking member, inserting thecatheter over the tracking member while leaving the cutting memberoutside the catheter, and expanding a portion of the catheter to movethe cutting member into cutting contact with the lesion to enlarge apassageway in the body lumen.

In some embodiments, the step of inserting a catheter over the trackingmember comprises reinserting the same catheter through which the cuttingmember and tracking member were initially inserted. In otherembodiments, a different catheter is utilized.

The catheter preferably includes an expandable balloon, and the step ofexpanding the catheter preferably includes the step of expanding aportion of the balloon to cause the cutting member to be moved radiallywith respect to the catheter. Preferably, the step of expanding aportion of the catheter causes a gap between the cutting member andtracking member to widen.

In some embodiments, the cutting member has a cutting edge opposite anedge facing the tracking member, and expansion of a portion of thecatheter forces the cutting edge into a diseased narrowed section withinthe lesion.

In preferred embodiments, the cutting member and tracking member areattached at their distal ends and inserted as a unit through the lumenof the catheter.

In some embodiments, the length of the tracking member can exceed thelength of the cutting member. In some embodiments the cutting member hasa first portion of a first configuration and a second portion of asecond configuration, the second portion including a cutting surface andthe first portion being atraumatic. In some embodiments, a height of thesecond portion is less than a height of the first portion.

In some embodiments, marker bands are provided on the tracking member.The tracking member can have a coil at a distal tip.

In another aspect, the present invention provides a method of treating alesion in a body lumen to enlarge a passageway in the body lumencomprising inserting a cutting member and tracking member into thevessel, inserting a catheter over the tracking member so the trackingmember extends through a first lumen of the catheter and the cuttingmember does not extend through, e.g. remains outside, the first lumen,and moving the cutting member away from the tracking member into cuttingcontact with the lesion to enlarge the passageway in the body lumen.

Preferably, the step of inserting a cutting member and tracking membercomprises the step of inserting the cutting member and tracking memberthrough a lumen of a catheter.

In some embodiments, the catheter through which the cutting and trackingmembers are initially inserted is the same catheter subsequentlyinserted over the tracking member. In other embodiments, a differentcatheter is utilized. In some embodiments, the step of moving thecutting member comprises the step of expanding a balloon of thecatheter. In preferred embodiments, the cutting member and trackingmember are wires and are attached at their distal end and inserted as aunit into the vessel.

In some embodiments, the tracking member has a coil tip. A heat shrinkcan be provided over an attachment region of the cutting and trackingmembers.

In some embodiments, the cutting member is substantially circular incross-section in a proximal region and substantially triangularcross-section in a distal region.

In another aspect, the present invention provides a device for treatinga lesion in a body lumen to enlarge a passageway in a body lumencomprising a cutting member having a proximal portion and a distalportion and a tracking member having a proximal portion and a distalportion. The cutting member and tracking member are connected at theirdistal portions and insertable into the body lumen as a unit, thecutting member configured for movement in a direction transverse to alongitudinal axis of the tracking member to widen a gap between thecutting member and tracking member at least at a distal region.

In some embodiments, the cutting member has a cutting surface on a firstsurface opposite a second surface facing the tracking member. In someembodiments, the cutting member has a cutting surface with a flat edgeon an edge opposite a surface facing the tracking member. In someembodiments, the second surface has a convex surface. The trackingmember can include a plurality of marker bands.

In another aspect, the present invention provides a system for treatinglesions in a body lumen to enlarge a restriction in the body lumencomprising a catheter having a lumen and an expandable portion and acutting assembly including a cutting member and tracking member, thetracking member attached to the cutting member. The expandable portionof the catheter is expandable to move the cutting member in a directiontransverse to a longitudinal axis of the tracking member, the cuttingmember having a cutting surface configured to treat the lesion toenlarge a passageway in the body lumen when moved by the expandableportion of the catheter.

In some embodiments, the cutting member and tracking member areconnected at distal regions thereof. The tracking member can include aplurality of marker bands. The cutting member in some embodiments issubstantially circular in cross-section in a proximal region andsubstantially triangular in a distal region. In preferred embodiments,the expandable portion of the catheter comprises an inflatable balloon.The tracking member can have a coil at a distal end and a heat shrinkcan be positioned over the attachment region of the cutting and trackingmembers.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present invention are described hereinwith reference to the drawings wherein:

FIG. 1 is a perspective view of a conventional balloon catheter and afirst embodiment of the cutting wire assembly (unit) of the presentinvention and showing the balloon expanded;

FIG. 1A is a perspective view of the cutting assembly of FIG. 1;

FIG. 1B is a perspective view similar to FIG. 1A showing the shrink wrapover a distal portion;

FIG. 2A is an enlarged perspective view of the area of detail of FIG. 1showing a portion of the cutting wire in accordance with one embodiment;

FIG. 2B is a perspective view similar to FIG. 2A showing anotherembodiment of the cutting wire;

FIG. 2C is a perspective view similar to FIG. 2A showing yet anotherembodiment of the cutting wire;

FIG. 2D is a perspective view similar to FIG. 2A showing anotherembodiment of the cutting wire;

FIG. 2E is a perspective view similar to FIG. 2A of yet anotherembodiment of the cutting wire;

FIG. 3A is a perspective view of another embodiment of the cutting wireassembly;

FIG. 3B is a close up perspective view of a distal portion of thecutting assembly of FIG. 3A.

FIG. 4A is a cross-sectional view of the cutting wire taken along line4A-4A of FIG. 3B;

FIG. 4B is a cross-sectional view of the cutting wire taken along line4B-4B of FIG. 3B;

FIGS. 5-5E illustrate the method steps for use of the cutting wireassembly of the present invention, the drawings showing cross-sectionalviews, wherein

FIG. 5 illustrates a conventional balloon catheter inserted over aconventional guidewire;

FIG. 5A illustrates withdrawal of the conventional guidewire;

FIG. 5B illustrates insertion of the cutting and tracking members of thepresent invention through the balloon catheter lumen;

FIG. 5C illustrates withdrawal of the balloon catheter leaving thecutting and tracking members within the vessel lumen;

FIG. 5D illustrates the balloon catheter inserted over the trackingmember; and

FIG. 5E illustrates expansion of the balloon of the balloon catheter toforce the cutting wire into cutting contact with the lesion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings wherein like reference numeralsidentify similar or like components throughout the several views, thecutting assembly of the present invention includes a cutting member (orelement) and a tracking member (or element). More, specifically, cuttingassembly includes an assembly 10 having a tracking member, designatedgenerally by reference numeral 30 and preferably in the form of a wire,and a cutting member, designated generally by reference numeral 20 andpreferably in the form of a wire. As discussed in more detail below, thetracking wire 30 and cutting wire 20 are preferably attached at a distalportion so they are insertable as a unit. The wire assembly 10, asdescribed below, can be used with a conventional catheter, such as anangioplasty catheter.

The device of the present invention functions to treat the stenoticlesion inside the vessel wall, thereby opening or enlarging thepassageway in the vessel which was restricted. The stenosis can be aresult of plaque buildup, endothelial growth, blood clots, etc. Thedevice can also be used to treat other lesions restricting passagewaysin other body lumens.

With reference to FIGS. 1 and 5C, cutting member in the form of a wire20 has a distal portion 23 which is connected to a distal portion 32 ofa tracking member in the form of a wire 30. In the illustratedembodiment, a distalmost tip 23 of the cutting wire 20 is attached tothe tracking or guidewire 30. One way of attachment is to twist thewires together. Other methods of attachment are also contemplated suchas welding, bonding or placement of a separate element such as a collarover the end of the wires to frictionally engage the wires. The cuttingwire 20 remains unattached proximal of the distal connection(attachment) region to enable it to be separated from the tracking wire30 e.g. moved transversely with respect to the longitudinal axis of thetracking wire 30. In FIG. 5C, the initial position of the wires 20, 30are shown; in FIGS. 5D and 5E the wires 20, 30 are further separated asdescribed in detail below.

Tracking member has a coil tip 33 for flexibility. A heat shrink wrap 35can be placed over the connection region of the cutting wire 20 and atracking wire 30. Marker bands 34 can be provided for imaging.

Note the tracking wire and cutting wire can be of substantially the samelength, both extending out of the body for reinsertion of a catheterover the tracking wire as described below. Alternatively, they can be ofdifferent lengths.

Various configurations of the cutting wire 20 are illustrated toeffectively treat lesions. In the embodiment of FIG. 2A, the wire 70 issubstantially triangular in cross section forming a V-shaped cuttingsurface 72 on a first surface opposite a second surface facing thetracking wire 30. In the embodiment of FIG. 2B, a cutting edge 76 onfirst surface 78 a of cutting wire 78 with a substantially planar outeredge extends from the substantially planar base 79. In FIG. 2C, asurface 82 of the wire 80 opposite the cutting surface 84 and facing thetracking wire 30 is convex. This surface 82 can conform to the outersurface of the catheter balloon. Two or alternatively three sides of thecutting wire can be convex as in sides 86 a, 86 b, 86 c of wire 85 ofFIG. 2D. In the embodiment of FIG. 2E, wire 88 is trapezoidal in crosssection with a cutting surface 89 on the outer surface. Other shapes arealso contemplated, including but not limited to polygonal shapes thatare substantially: square, rectangular, rhombus, hexagonal, pentagonal,octagonal, diamond shaped, etc. A round or oval wire cross-section witha sharpened surface is also contemplated. Caltrop shapes and upside downT-shapes are also contemplated.

Note, if desired, only a portion of the cutting wire (member) can havethe cutting edge or surface, e.g. the distal region, with a remainingportion being atraumatic and non-cutting. This is shown for example inthe embodiment of FIGS. 3A and 3B where wire 51 of cutting assembly 50has a distal portion having a cutting edge 54. (Although shown as asubstantially triangular cross-section, other cross-sectional shapes arealso contemplated including those discussed above). Proximal of distalportion 52, the portion 56 is atraumatic and can be substantiallycircular in cross-section as shown in FIG. 4B. (Other shapes are alsocontemplated). The distal region of wire 51 can be conical and can havean atraumatic surface. Note the height of the cutting surface region canbe less than the height (e.g. diameter) of the atraumatic portion 56.

A coil such as coil 33, can be provided at the distal tip of trackingmember (wire) 55. Several marker bands 58 are provided on tracking wire55 for imaging. A heat shrink wrap such as shrink wrap 35 of FIG. 1Bwhich covers the distal and connecting region of wires 20 and 30 can beprovided over the distal tip and connection region of the cutting andtracking wires 51, 55 of FIG. 3B.

One method of use of the wire assembly 10 of the present invention willnow be described. The method is described for using wire assembly 10,but it should be appreciated that the same method can be used for wireassembly 50 (and for the other cutting wire configurations). Initially,a conventional catheter 100, such as conventional angioplasty catheter,is inserted over a conventional guidewire G to the treatment site asshown in FIG. 5. Guidewire G extends through a lumen 62 in the catheter60. Access to the vessel can be obtained through the femoral artery orvein for example. Note the proximal end of the catheter 60 and guidewireG extend outside the patient's body. The angioplasty catheter 60 has aninflatable balloon 64 which is in fluid communication with an inflationlumen of the catheter as is conventional. At the target site, inflationof the balloon 64 expands the balloon 64 to expand the lesion B andwiden the lumen of the vessel V.

If the stenotic lesion cannot be successfully opened by a conventionalballoon due to lack of force, the wire assembly 10 (or assembly 50) ofthe present invention can be utilized. In this case, the guidewire G isremoved from the guidewire lumen 62 of the catheter 60 (see FIG. 5A) andthe wire assembly 10 (or 50) is inserted through the lumen 62 as shownin FIG. 5B. Thus, by insertion through the lumen 62, the trackingguidewire 30 (or 55) and cutting wire 20 (or 51) of wire assembly 10 (or50) are inserted to the target site.

Next, the catheter 60 is removed from the treatment site and vessel, andremoved from the body, leaving the wire assembly 10 at the target siteas shown in FIG. 5C. The catheter 60 is then reinserted over proximalend of tracking wire 30. Note that instead of reinserting the samecatheter used in the step of FIG. 5, alternatively, a different ballooncatheter (or catheter with other expandable member) can be inserted. Ineither event, the catheter is inserted over the proximal portion of thetracking wire 30 such that the tracking wire 30 extends through thelumen 62; however, cutting wire 20 remains outside the lumen 62 and thusdoes not extend through lumen 62 as shown in FIG. 5D. In this manner,the tracking wire 30 provides a guide for the catheter 60 to the targetsite, while the cutting wire 20 remains adjacent an outer surface of thecatheter 60 for subsequent expansion into contact with the lesion. Asshown in FIG. 5D, there is an increased gap 65 between the cutting wire20 and tracking wire 30 caused by the catheter 60 positioned between thetwo wires 20, 30.

To expand or move the wire 20 transversely with respect to thelongitudinal axis of the tracking wire 30 (and transverse to thelongitudinal axis of the catheter 60), the balloon 64 is inflated,forcing the cutting wire 20 radially and into contact with the lesion Bso the cutting edge or surface can treat the lesion. It should beappreciated that instead of a balloon, a mechanical expander or otherstructure can be used to force the cutting wire 20 into contact with thelesion. If desired, the balloon 64 can be deflated and the wire assemblyeasily rotated to another position for subsequent transverse movement bythe cutting wire into contact with another region of the lesion B. Inthis manner, the select portions of the stenosis can be treated, as thecutting wire 20 is expanding in one direction. The cutting wire assembly50 can be used in a similar manner.

As can be appreciated, the method described above utilizes the samecatheter for the initial step (FIG. 5) as well as for the subsequentstep of reinsertion for placement only over the tracking wire 30 (FIG.5D). However, it is also contemplated that a different catheter can beused for insertion over tracking wire 30 in the step of FIG. 5D.

As can be appreciated, the wire assembly 10 can accommodate ballooncatheters having relatively small guidewire lumens.

Also, although access is described through the femoral artery, otherapproaches to the target site are also contemplated. Additionally,although described for use to treat lesions in vessel lumens, it canalso be used to remove other structures constricting the passageway inthe vessel or in other body lumens.

The cutting and tracking components are illustrated as wires, but otherstructures for the cutting member and tracking member are alsocontemplated such as a hard plastic cut tube or a metal hypotube. Themetal hypotube can be formed with a cutting surface or alternativelyhave a cutting member such as a cutting tube attached thereto.

The cutting wire assembly of the present invention as described can beused in various vessels including for example, veins such as the femoralveins, grafts such as dialysis grafts, etc. Other vessels are alsocontemplated such as use in carotid arteries, coronary arteries, thedescending aorta and renal arteries, the external iliac and internaliliac arteries and the common femoral and deep femoral arteries.Applications for this device include, but are not limited to, treatingstenotic venous and arterial anastomosis, lesions resistant toconventional angioplasty, stent restenosis, and vessels with buildup ofintima, etc.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

1. A system for treating a lesion in a body lumen of a patient toenlarge a passageway in the body lumen comprising: a catheter having alumen and an expandable portion; and a cutting assembly including acutting member and a tracking member, the tracking member attached tothe cutting member, wherein the expandable portion of the catheter isexpandable to move the cutting member in a direction transverse to alongitudinal axis of the tracking member, the cutting member having aproximal portion and a distal portion, the proximal portion configuredto extend outside the patient when the cutting member is positioned inthe body lumen adjacent the lesion, the cutting member having a cuttingsurface configured to treat the lesion to enlarge the passageway in thebody lumen when moved by the expandable portion of the catheter. 2-19.(canceled)